Signs Your Car’s AC Needs to be Recharged (2024)

Understanding the Importance of AC Recharge

Refrigerant cycles through the air conditioning system to transfer heat from the cabin to the engine bay where it can be dissipated into the atmosphere. When the system is full, the low-pressure refrigerant passing through the evaporator inside the car absorbs heat to make the air feel cooler. But if the AC refrigerant charge is low, the refrigerant doesn’t get as cool as it should, and the compressor needs to work overtime to push refrigerant into the high-pressure side.

When that happens, there’s additional strain on the compressor and it can fail prematurely or stop cycling. And with low charge, the AC doesn’t function as well as it should inside your cabin either.

Signs That Your Car’s AC Needs to be Recharged

There are a handful of signs your AC needs to be recharged in your car. You may experience one or more of them, but it often depends on your climate and how your AC typically performs.

• AC isn’t blowing cold air. Clearly, if there isn’t cold air blowing from your dash vents, it can be a symptom of a system that’s low on refrigerant. Don’t rely on this symptom alone, though, since almost all AC issues will cause it.
• The AC clutch doesn’t engage. When the refrigerant is low, the compressor clutch may not engage at all, or it might only engage sporadically, like when you rev the engine.
• AC only cools when you’re accelerating. Low charge can mean the compressor can’t circulate refrigerant well at low engine speeds, but some cold air comes from the vents when you’re driving.
• The windows won’t clear. AC removes moisture from the cabin air on defrost settings. If your windows aren’t clearing, odds are that the refrigerant is low.
• You’ve replaced AC components. When you open the AC’s closed system, refrigerant escapes into the atmosphere and will need to be recharged.

Related: How to Replace a Car AC Compressor Yourself

Potential Drawbacks and Limitations of DIY AC Recharge

While you can recharge your AC at home, it’s quite difficult to actually verify that there isn’t a bigger problem that needs attention. If there’s a leak, whether large or small, you could be adding refrigerant for it to quickly disappear again.

When to Seek Professional Help

And if there is a leak, vacuum testing should be done by someone certified to work on AC systems, who can also recover the remaining refrigerant from the system. If your car’s AC loses its charge often, say more than once every three years, you should have a professional diagnose it, repair the problem, and recharge the system.

At your local AutoZone store, find all of the parts and fluids you need to take care of your car including AC refrigerant kits. If you decide that it’s too big a job to tackle on your own, let AutoZone help you find qualified professional mechanics through our Shop Referral Program.

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